The present invention relates to a communication method and a communication system for performing transmitting/receiving of signals between a base station and a plurality of mobile stations by wireless propagation, and particularly relates to a communication method and a communication system that enable the mobile station side to designate conditions of communications such as transmitting power, communication quality and the like when signals are transmitted.
In a large scale communication system, a service area has been heretofore formed of a plurality of wireless zones. Each respective wireless zone has a base station equipped with a transmitter and a receiver and communicates bidirectionally with a plurality of mobile stations, each equipped with a transmitter and a receiver, through wireless communication channels.
FIG. 8 is a schematic diagram showing a wireless zone according to a prior art communication system. In FIG. 8, a base station 1 acting as a relay station for communications and the like is set up in a wireless zone 3, where mobile stations 51, 52, . . . , 5n such as portable telephones and the like for wireless communications with the base station 1 are located. The base station 1 is performing wireless communications with the mobile stations 51, 52, . . . , 5n with predetermined levels of transmitting power 61, . . . , 6n and the communication area to be covered by the base station 1 is indicated by the wireless zone 3. When wireless communications are performed between the base station 1 and a plurality of the mobile stations 51, 52, . . . , 5n, respectively as FIG. 8 shows, transmitting power of signals has a great influence on communication quality. Therefore, many methods for controlling transmitting power have been adopted heretofore. A description is given to a prior art communication system employing a method of controlling transmitting power on the following.
The prior art communication system has transmitting frequencies for signals in wireless communications assigned to respective mobile stations 51, . . . , 5n that are different from one another, and also transmitting powers 61, . . . , 6n of signals between the base station 1 and the mobile stations 51, . . . , 5n are set up in such a way that the mobile station located the farthest from the base station 1 (the mobile station 5n located on the boundary of the wireless zone 3 in FIG. 8) is allowed to communicate with the base station 1, and transmitting powers of all the mobile stations 51, 5n are made the same. Therefore, as the distance between the base station 1 and the respective mobile stations 51, . . . , 5n becomes the smaller, the signal power level (signal energy level) of the received signal becomes the higher.
According to the prior art communication system as described in the above, as long as the mobile stations 51, . . . , 5n are located within the wireless zone 3 of the base station 1, it is made possible for wireless communications to be performed between the base station 1 and the respective mobile stations 51, . . . , 5n.
Other prior art communication systems such as a spread spectrum communication system and the like use the same frequency as the signal propagating wave frequency in wireless communications throughout all the mobile stations 51, . . . , 5n. Also, transmitting powers 61, . . . , 6n of signals between the base station 1 and the respective mobile stations 51, . . . , 5n are made different for each respective mobile station in order to have the signal power level of a signal received by the base station 1 from each of the mobile stations 51, . . . , 5n made the same with one another. In other words, transmitting power of a signal between the base station 1 and any one of the mobile stations 51, . . . , 5n is made proportionate to the distance between the base station 1 and the above one of the mobile stations 51, . . . , 5n, thereby making it possible for the signal power level of a signal received by the base station 1 from any one of the mobile stations 51, . . . , 5n to be the same with one another.
Accordingly, the prior art communication systems allow wireless communications to be performed among a plurality of mobile stations 51, . . . , 5n by using the same frequency as the signal propagating wave frequency for all the mobile stations 51, . . . , 5n.
A method for controlling transmitting power levels of signals in a communication system by assigning the same frequency to the propagating wave frequency for all the signals as described in the above is disclosed in a Japanese Patent Unexamined Publication numbered H9-326753. This method for controlling transmitting power levels allows a transmitting power level to be controlled up and down within a predetermined range according to the quality of received signals and also allows the charge management office to be informed of the intensity of received signals.
However, the prior art communication systems and the method for controlling transmitting power levels as disclosed by the Japanese Patent Unexamined Publication H9-326753 have a problem of inability to set up the transmitting power level, quality of communications and the like arbitrarily at the mobile station side. Therefore, in case where the information transmitted via wireless communications happens to be a computer program and the like, for example, the mobile station side (user side) has not been allowed to designate the conditions of wireless communications as needed according to the information to be transmitted as in the case where transmitting power, quality of communications and the like are to be enhanced when such information as a computer program add the like is transmitted via wireless communications and to be degraded when such information as voice data and the like is transmitted, for example.
In addition, in order to guarantee a high grade in communication quality, a transmitting power level exceeding a predetermined level has been maintained throughout a specific wireless zone, thereby keeping a given level of communication quality regardless the nature of information to be transmitted. In general, a transmitting power level is closely related to the level of fee charged to a mobile station (user) and for a certain user who is just involved with a voice data it may be ending up with a higher communication quality level than what is really needed, thereby causing sometimes a problem of bringing about an inappropriately high communication cost. On the other hand, with a communication system where the transmitting power level is set to an inadvertently low level, such provisions as sending the same data several times to ascertain the agreement of received data and the like, for example, are put in place in order to maintain a given level in communication quality for such information as a computer program and the like, thereby creating a problem of increasing communication costs due to prolonged communication time.
The present invention deals with the problems as described in the above and the objective thereof is to provide a communication method and communication system that enable the establishment of the best conditions for communications according to the nature of information to be transferred and the communication environment by designating as needed at the mobile station side such conditions for wireless communications as a transmitting power level, a value of communication quality and the like.
The present invention also aims at providing a communication method and communication system to allow the communication fees to be determined according to the conditions of communications designated at the mobile station side in consideration of the nature of information to be transferred and also the optimization of communication costs in accordance with the communication conditions.
For achieving the foregoing objects, a communication method in a first exemplary embodiment of the present invention is a method for performing wireless communications between a base station and a plurality of mobile stations, comprising the steps of:
(a) designating an upper limit p of transmitting power for a signal to be transmitted from the base station at the mobile station side;
(b) transmitting the designated upper limit p of transmitting power to the base station from the mobile station side;
(c) receiving at the base station the upper limit p of transmitting power from the mobile station side; and
(d) determining an upper limit P of transmitting power of the base station to the mobile station side according to the upper limit p.
In the step (d) of the communication method in the first exemplary embodiment of the present invention, (cxe2x80x2) the status of communication congestion of mobile stations engaged in communication is being watched at the base station and the upper limit P may be allowed to be determined according to the extent of communication congestion and the upper limit p, or the status of communication congestion of mobile stations engaged in communication may be watched via the summation of the upper limit P of the base station""s communication power level against each respective mobile station communicating with the base station, or further the status of communication congestion may be watched via the summation of the upper p of each respective communication power level designated by the mobile stations engaged in communication.
Also, in the step (d) of the communication method in the first exemplary embodiment of the present invention, the upper limit P of transmitting power may be determined according to the upper limit p so as to satisfy an equation, P=kxc2x7p (, where 0 less than kxe2x89xa61), and when the upper limit p is smaller than an upper limit actually in use, the upper limit P is also allowed to replace the upper limit p. Further, when the upper limit P of transmitting power used in the on-going communications is to be changed to the upper limit p, the upper limit used in communicating with mobile stations except for the mobile station that has transmitted the upper limit p is allowed to be reduced if the summation of those upper limits exceeds a predetermined threshold value.
Furthermore, in the step (d) of the communication method in the first exemplary embodiment of the present invention, when the upper limit P of transmitting power is about to be changed to the upper limit p, the on-going upper limit P is allowed to be maintained if the summation of the upper limit p of each respective mobile station engaged actually in communication exceeds a predetermined threshold value. In addition, when the upper limit P of transmitting power is about to be changed to the upper limit p, the upper limit P is allowed to be maintained if the summation of the upper limit of each respective mobile station engaged actually in communication exceeds a predetermined threshold value, and the upper limit P is also allowed to be made the upper limit p if the summation of each respective upper limit does not exceed a predetermined threshold value. At this time, (e) if the upper limit P now in use at the base station is maintained, the maintaining signal is allowed to be transmitted to mobile stations, and if the upper limit P is renewed, the renewed signal is also allowed to be transmitted to mobile stations.
Here, the threshold value as referred to in the above can be made the maximum value of communication power that the base station or mobile stations can output.
For achieving the foregoing objects, a communication method in a second exemplary embodiment of the present invention comprises the steps of:
(a) designating arbitrarily at the mobile station side an upper limit pxe2x80x2 of transmitting power of a signal transmitted from the mobile station;
(b) transmitting from the mobile station side the designated upper limit pxe2x80x2 of transmitting power to the base station;
(c) receiving at the base station the upper limit pxe2x80x2 of transmitting power transmitted from the mobile station side;
(d) determining an upper limit Pxe2x80x2 of transmitting power of the mobile station according to the upper limit pxe2x80x2 at the base station; and
(e) transmitting the determined upper limit Pxe2x80x2 of the mobile station""s transmitting power to the mobile station side from the base station.
With the communication methods in the first and second exemplary embodiments of the present invention as described in the above,
in the step (a), the upper limit p of transmitting power of a signal from the base station and the upper limit pxe2x80x2 of transmitting power of a signal from the mobile station may also be designated arbitrarily;
in the step (b), the designated upper limits p and pxe2x80x2 of transmitting power may also be transmitted, respectively, to the base station;
in the step (c), the upper limits p and pxe2x80x2 of transmitting power transmitted, respectively, from mobile stations may also be received; and
in the step (d), the upper limit P of transmitting power of the base station against the mobile station may also be determined according to the upper limit p and the upper limit Pxe2x80x2 of the mobile station""s transmitting power may also be determined according to the upper limit pxe2x80x2.
Here, (e) the upper limit Pxe2x80x2 of transmitting power determined for a particular mobile station is transmitted to the particular mobile station at the base station;
(f) communications are performed with the particular mobile station by using a transmitting power level Pp that does not exceed the determined upper limit P of transmitting power; and
(bxe2x80x2) at mobile stations, communications can be performed with the base station by a transmitting power level Ppxe2x80x2 that does not exceed the determined upper limit Pxe2x80x2 of transmitting power.
In addition, (g) at the base station, an amount of fee charged to each respective mobile station can be determined according to the upper limit P of transmitting power of a signal sent from the base station to each mobile station, or an actual value Pp of transmitting power against each mobile station, or the upper limit Pxe2x80x2 of transmitting power of each mobile station, or an actual value Ppxe2x80x2 of transmitting power of each mobile station.
Further, in the step (a) a transfer speed v or vxe2x80x2 of the transmitted signal is arbitrarily designated in place of the upper limit p or pxe2x80x2, respectively, in the step (b) the transfer speed v or vxe2x80x2 is sent to the base station in place of the upper limit p or pxe2x80x2, respectively, and in the step (c) the base station receives the transfer speed v or vxe2x80x2 and can also apply a conversion to the upper limit p or pxe2x80x2 of transmitting power according to the transfer speed v or vxe2x80x2, respectively.
Further, in the step (a) a target value q of communication quality in wireless communications with the base station is designated arbitrarily, in the step (b) the designated target value q of communication quality is sent to the base station, in the step (c) the target value q of communication quality sent from a particular mobile station is received and in the step (d) a target value Q of communication quality in wireless communications with the particular mobile station may also be determined according to the received target value q of communication quality.
At this time, (h) the base station sends to a mobile station the information that a signal has been sent with an upper limit P of transmitting power and the target value Q of communication quality has not been achieved, and at the mobile station (i) the communications with the base station are terminated upon receiving the foregoing information, or (i) a new upper limit p1 that is larger than the upper limit P of the on-going transmitting power level is sent to the base station upon receiving the foregoing information, or (i) a new target value q1 that is lower than the target value Q of the on-going communication quality is sent to the base station upon receiving the foregoing information, or (i) a new upper limit p1 that is larger than the upper limit P of the on-going transmitting power level and a new target value q1 that is lower than the target value Q of the on-going communication quality are sent to the base station upon receiving the foregoing information, and (j) at the base station the steps (c) to (d) may also be performed according to the upper limit p1 and target value q1.
As an alternate approach, at the base station (h) a value q2 of communication quality of a signal sent from a particular mobile station is transmitted to the particular mobile station and, at mobile stations, communications with the base station are being performed with the upper limit Pxe2x80x2 of transmitting power of the foregoing particular mobile station and when the value q2 of communication quality is found to be lower than the target value Q of communication quality, (i) the communications with the base station are terminated, (i) a new upper limit p1xe2x80x2 of the mobile station""s transmitting power level that is larger than the upper limit Pxe2x80x2 of the on-going mobile station""s transmitting power is sent to the base station, or (i) a new target value q1 of communication quality that is lower than the target value Q of the on-going communication quality is sent to the base station, or (i) a new upper limit p1xe2x80x2 that is larger than the upper limit P of the on-going transmitting power level and a new target value q1 of communication quality that is lower than the target value Q of the on-going communication quality are sent to the base station, and (j) at the base station the steps (c) to (d) may also be performed according to the upper limit p1xe2x80x2 and target value q1 of mobile stations.
Also, for achieving the foregoing objects, a communication method in a third exemplary embodiment of the present invention comprises the steps of:
(a) designating arbitrarily at a mobile station a target value q of communication quality in wireless communications with the base station;
(b) transmitting the designated target value q of communication quality to the base station;
(c) receiving at the base station the target value q of communication quality sent from the mobile station; and
(d) determining a target value Q of communication quality in wireless communications with the mobile station according to the received target value q of communication quality.
In addition to the foregoing setup, with the communication method in the third exemplary embodiment of the present invention, (cxe2x80x2) the status of communication congestion of mobile stations engaged in communication is being watched at the base station and in the step (d) the target value Q of communication quality can also be determined according to the status of communication congestion and the target value q. Also, in the step (cxe2x80x2) the status of communication congestion against the mobile stations engaged in communication may be watched via the summation of the target value Q of communication quality for each respective mobile station engaged in communication, or further the status of communication congestion may be watched via the summation of the target value q of communication quality designated by each respective mobile station engaged in communication.
Also, in the step (d) of the communication method in the third exemplary embodiment of the present invention, when the received target value q of communication quality is lower than a target value of communication quality used in communications with a mobile station, the target value Q of communication quality used in wireless communications with the mobile stations is allowed to be used as the received target value q of communication quality, and in case where the summation of target values of communication quality in wireless communications with each respective mobile station engaged in communication exceeds a predetermined threshold value when the target value Q of communication quality used in wireless communications with mobile stations is changed to the received target value q of communication quality, the target value of communication quality used in wireless communications with a mobile station different from the mobile station that has transmitted the target value q of communication quality can also be reduced.
Further, in the step (d) of the communication method in the third exemplary embodiment of the present invention, when the target value Q of communication quality in wireless communications with mobile stations is to be changed to the received target value q of communication quality, if the summation of target values of communication quality in wireless communications with each respective mobile station engaged in communication exceeds a predetermined threshold value, the target value Q of communication quality used in wireless communications with mobile stations is maintained, and if the summation of the target values of communication quality does not exceed the predetermined threshold value, the target value Q of communication quality used in wireless communications with mobile stations may also be allowed to be the received target value q of communication quality.
At this time, (e) when the target value Q of communication quality used in wireless communications with mobile stations is further maintained at the base station, a signal of maintaining the target value Q of communication quality is sent to mobile stations and when the target value Q of communication quality is renewed, a signal of renewing the target value Q may also be sent to mobile stations.
In the foregoing, it is recommended that the threshold value should be the upper limit of the summation of values representing the communication quality that can be maintained by the base station.
With the communication method in the third exemplary embodiment of the present invention, (f) a communication fee charged to a mobile station can be determined at the base station according to the target value Q of communication quality used in wireless communications with the mobile station.
In the step (d) of the communication method in the third exemplary embodiment of the present invention, the target values q and Q of communication quality can also be handled through a process of converting to thermal noise power, a reciprocal of a bit error rate (BER) per unit time, a ratio of signal power after back-diffusion to thermal noise power or a ratio of signal power per bit to noise power density.
It is recommended that with the communication methods in the first to third exemplary embodiments of the present invention, the wireless communications between the base station and a plurality of mobile stations should also be employing spread spectrum communications. At this time, in the step (d) of the communication method in the third exemplary embodiment of the present invention, the target values q and Q of communication quality can also be handled through a process of converting to thermal noise power derived by calculation from a ratio of signal power after back-diffusion to thermal noise power, or thermal noise power calculated from a ratio of signal power per bit to noise power density and a diffusion rate of spread spectrum communications. Further, the foregoing method of spread spectrum communications may also be replaced with a method of code division multiple access (CDMA) communications.
For achieving the aforementioned objects, the communication system in a first exemplary embodiment of the present invention comprises:
a base station; and
a plurality of mobile stations to perform wireless communications between the base station and the plurality of mobile stations, the plurality of mobile stations having, respectively:
a transmitting power designating means to designate an upper limit p of transmitting power for a signal transmitted from the base station; and
a transmitting means to send the upper limit p of transmitting power designated by the transmitting power designating means, and the base station having:
a receiving means to receive the upper limit p of transmitting power sent from mobile stations; and
a transmitting power determining means to determine an upper limit P of transmitting power when a signal is sent to mobile stations.
Also, for achieving the aforementioned objects, a communication system in a second exemplary embodiment of the present invention comprises:
a base station; and
a plurality of mobile stations, the plurality of mobile stations having, respectively:
a transferring speed designating means to designate a transferring speed v of a signal sent from the base station; and
a transmitting means to send the transferring speed v designated by the transferring speed designating means to the base station, and the base station having:
a receiving means to receive the transferring speed v sent from mobile stations;
a transmitting power converting means to convert an upper limit p of transmitting power according to the transferring speed v; and
a transmitting power determining means to determine an upper limit P of transmitting power according to the upper limit p of transmitting power when a signal is sent to mobile stations.
Further, with the communication system in the first or second exemplary embodiment of the present invention as described in the above, such arrangements as:
the transmitting power designating means of a mobile station designates an upper limit pxe2x80x2 of transmitting power for a signal sent from the mobile station;
the transmitting means of the mobile station sends the upper limit pxe2x80x2 to the base station;
the receiving means of the base station receives the upper limit pxe2x80x2 sent from the mobile station; and
the transmitting power determining means of the base station determines an upper limit Pxe2x80x2 of transmitting power according to the upper limit pxe2x80x2 when a signal is sent from the mobile station to the base station, may also be made.
Still further, with the communication system in the first or second exemplary embodiment of the present invention as described in the above, such arrangements as:
the transferring speed designating means of a mobile station designates a transferring speed vxe2x80x2 for a signal sent from the mobile station; the transmitting means of the mobile station sends the transferring speed vxe2x80x2 to the base station;
the receiving means of the base station receives the transferring speed vxe2x80x2 sent from the mobile station; and
the transmitting power determining means of the base station derives an upper limit pxe2x80x2 of transmitting power by conversion according to the transferring speed vxe2x80x2 and determines an upper limit Pxe2x80x2 of transmitting power via the upper limit pxe2x80x2 when a signal is sent from the mobile station to the base station, may also be made.
In addition, with the communications systems of the present invention as described in the above, the base station may have a communication congestion status detecting means to detect the status of communication congestion of mobile stations engaged actually in communication among the plurality of mobile stations, and the transmitting power determining means of the base station may be allowed to have the ability of determining the upper limit P of transmitting power used at the time of transmitting a signal to a mobile station according to the status of communication congestion detected by the communication congestion status detecting means and the upper limit p. At this time, the communication congestion status detecting means may also be allowed to detect the status of communication congestion via the summation of the upper limit P of communication power of each respective mobile station engaged actually in communication among the plurality of mobile stations, or the summation of the upper limit p of communication power designated by each respective mobile station engaged actually in communication.
Further, the transmitting power determining means may also be set up so as to determine the upper limit P of transmitting power of a mobile station in such a way as satisfying an equation, P=kxc2x7p (, where 0 less than kxe2x89xa61), according to the upper limit p.
When the upper limit p or pxe2x80x2 is smaller than the upper limit P or Pxe2x80x2 that is used in communication, such an arrangement for the transmitting power determining means as determining the upper limit P or Pxe2x80x2 of transmitting power to be the upper limit p or pxe2x80x2, respectively, may also be possible.
When the transmitting power determining means is provided with the ability of determining the upper limit P of transmitting power used in communication to be the upper limit p, in case where the summation of the upper limit P of transmitting power of each respective mobile station engaged actually in communication among the plurality of mobile stations exceeds a predetermined threshold value, such an arrangement as maintaining the upper limit P used in communication is also possible, and further in case where the summation of the upper limit P does not exceed the predetermined threshold value, such an arrangement as determining the upper limit P to be renewed as the upper limit p may also be possible. When the upper limit P of transmitting power used in communicating with mobile stations is determined to be the upper limit p, the upper limit of transmitting power used in communicating with mobile stations different from the mobile station that has transmitted the upper limit p may also be reduced in case where the summation of the upper limit of transmitting power of each respective mobile station engaged actually in communication among the plurality of mobile stations exceeds a predetermined threshold value.
Further in the foregoing, if the base station determines for the transmitting power determining means to maintain the upper limit P, the base station may also be allowed to have a transmitting means to send a signal for maintaining the upper limit P to mobile stations, and if the upper limit P of transmitting power is renewed, a renewal signal of the upper limit P may also be transmitted to mobile stations.
Here, the foregoing threshold value is allowed to be the maximum value of communication power that the base station can put out.
For achieving the aforementioned objects, a communication system in a third exemplary embodiment of the present invention comprises:
a base station; and
a plurality of mobile stations, each of the plurality of mobile stations having, respectively:
a transmitting power designating means to designate an upper limit pxe2x80x2 of transmitting power for a signal transmitted from the mobile station; and
a transmitting means to send the upper limit pxe2x80x2 of transmitting power designated by the transmitting power designating means to the base station, and the base station having:
a receiving means to receive the upper limit pxe2x80x2 of transmitting power sent from mobile stations;
a transmitting power determining means to determine an upper limit Pxe2x80x2 of transmitting power for mobile stations via the upper limit pxe2x80x2 received at the receiving means; and
a transmitting means to send the upper limit F determined at the transmitting power determining means to mobile stations.
Also, for achieving the aforementioned objects, a communication system in a fourth exemplary embodiment of the present invention comprises:
a base station; and
a plurality of mobile stations, each of the plurality of mobile stations having, respectively:
a transferring speed designating means to designate a transferring speed vxe2x80x2 of
a signal sent from the base station; and
a transmitting means to send the transferring speed vxe2x80x2 designated by the transferring speed designating means to the base station, and the base station having:
a receiving means to receive the transferring speed vxe2x80x2 sent from mobile stations;
a transmitting power converting means to convert an upper limit pxe2x80x2 of transmitting power according to the transferring speed vxe2x80x2;
a transmitting power determining means to determine an upper limit Pxe2x80x2 of transmitting power according to the upper limit pxe2x80x2 of transmitting power; and
a transmitting means to send the upper limit Pxe2x80x2 determined by the transmitting power determining means to mobile stations.
With the foregoing communication systems of the present invention, a setup, wherein:
the base station has a transmitting means to send the upper limit Pxe2x80x2 to mobile stations;
each respective mobile station has a receiving means to receive the upper limit Pxe2x80x2 sent from the base station; and
each respective mobile station has a controlling means to control the transmitting power Ppxe2x80x2 of the transmitting means to less than the upper limit Pxe2x80x2, can be employed. In addition, the base station is also allowed to have a controlling means to control the transmitting power Pp of the transmitting means to less than the upper limit P.
Further, with the foregoing communication systems of the present invention, the base station may also have a charge determining means to determine the amount of a fee to be charged to respective mobile stations according to the upper limit P, transmitting power Pp, upper limit Pxe2x80x2 or transmitting power Ppxe2x80x2.
Still further, with the foregoing communication systems of the present invention, each of the plurality of mobile stations may also have, respectively:
a communication quality designating means to designate a target value q of communication quality in wireless communications with the base station; and
a controlling means to control the transmitting means so as to send the target value q designated by the communication quality designating means to the base station, and the base station may also have:
a controlling means to control a receiving means so as to receive the target value q sent from mobile stations and a communication quality determining means to determine a target value Q of communication quality in wireless communications with mobile stations according to the target value q.
Here, the base station may also be provided with a setup including:
a transmitting means to send to mobile stations such information that signals are being transmitted with the upper limit P of communication power and communication quality has not yet reached the target value Q, and respective mobile stations may also be provided with a setup including:
a receiving means to receive signals carrying the foregoing information from the base station; and
a controlling means to terminate communications with the base station upon receiving the information through the receiving means, or
to control the transmitting means so as to send to the base station a new upper limit p1 of transmitting power that is larger than the on-going upper limit P of transmitting power, or
to control the transmitting means so as to send to the base station a new target value q1 of communication quality that is lower than the on-going target value Q of communication quality, or
to control the transmitting means so as to send to the base station the new upper limit pl of transmitting power that is larger than the on-going upper limit P of transmitting power and the new target value q1 of communication quality that is lower than the on-going target value Q of communication quality.
With the foregoing communication systems of the present invention, each of the plurality of mobile stations may also have, respectively:
a communication quality designating means to designate a target value q of communication quality in wireless communications with the base station;
a controlling means to control a transmitting means so as to send the target value q designated by the communication quality designating means to the base station; and
a receiving means to receive signals and the like from the base station, and the base station may also have:
a controlling means to control a receiving means so as to receive the target value q sent from mobile stations;
a communication quality determining means to determine a target value Q of communication quality in wireless communications with mobile stations according to the target value q; and
a means to transmit to mobile stations an actual value q2 of communication quality detected from the signals received by the receiving means, and the base station has:
a controlling means to control the receiving means so as to receive the target value q sent from mobile stations;
a communication quality determining means to determine a target value Q of communication quality according to the target value q; and
a means to sent to mobile stations an actual communication quality value q2 of signals received at the receiving means, and the controlling means of mobile stations is provided with functions including:
controlling the transmitting means so as to terminate communications with the base station in case where, while the transmitting means sending signals with the upper limit Pxe2x80x2 of transmitting power, the value q2 of communication quality received through the receiving means is lower than the target value Q of communication quality; or
controlling the transmitting means so as to send to the base station a new upper limit p1xe2x80x2 of mobile station""s transmitting power that is larger than the upper limit Pxe2x80x2; or
controlling the transmitting means so as to send to the base station a new target value q1 of communication quality that is lower than the target value Q; or
controlling the transmitting means so as to send to the base station the new upper limit p1xe2x80x2 of mobile station""s transmitting power that is larger than the upper limit Pxe2x80x2 and the new target value q1 of communication quality that is lower than the target value Q.
For achieving the aforementioned objects, a communication system in a fifth exemplary embodiment of the present invention comprises:
a base station; and
a plurality of mobile stations to perform wireless communications between the base station and the plurality of mobile stations, the plurality of mobile stations having, respectively:
a communication quality designating means to designate a target value q of communication quality in wireless communications with the base station; and
a transmitting means to send the target value q designated by the communication quality designating means, and the base station having:
a receiving means to receive the target value q sent from mobile stations; and
a communication quality determining means to determine a target value Q of communication quality in wireless communications with mobile stations according to the target value q received at the receiving means.
With the communication system in the fifth exemplary embodiment of the present invention as described in the above, the base station may also have a setup comprising:
a communication congestion status detecting means to detect the status of communication congestion of mobile stations engaged actually in communication among the plurality of mobile stations; and
a communication quality determining means to determine a target value Q of communication quality in wireless communications with mobile stations according to the status of communication congestion detected by the communication congestion status detecting means and the target value q received via the receiving means. Alternatively, the status of communication congestion of mobile stations engaged actually in communication may also be detected by the communication congestion status detecting means according to the summation of target value Q of communication quality in wireless communications with respective mobile stations actually engaged in communication, or the summation of target value q of communication quality in wireless communications designated by respective mobile stations engaged actually in communication.
At this time, if the target value q is lower than the target value of communication quality used in wireless communications with mobile stations, the communication quality determining means may also be allowed to determine the target value q to be the target value Q of communication quality used in wireless communications with mobile stations. When the summation of target values of communication quality in wireless communications with respective mobile stations actually engaged in communication among the plurality of mobile stations exceeds a predetermined threshold value, the target value Q of communication quality used in wireless communications with mobile stations can be maintained or the target value of communication quality used in wireless communications with other mobile stations than the mobile station, which has transmitted the target value q, can be lowered. Conversely, when the summation of target values of communication quality does not exceed the predetermined threshold value, the target value Q of communication quality used in wireless communications with mobile stations can also be determined to be the target value q.
Furthermore, if the base station determines via the communication quality determining means that the target value Q of communication quality used in wireless communications with mobile stations is to be maintained, a target value Q maintaining signal is sent to mobile stations, and when the target value Q of communication quality is determined to be renewed, such a setup as having a transmitting means to send a renewal signal of the target value Q may also be adopted.
At this time, the foregoing threshold value can be made the upper limit of the summation of the communication quality that the base station can maintain.
Also, in the foregoing communication system in the fifth exemplary embodiment of the present invention, the base station can be set up so as to have a charge amount determining means to determine a fee charged to each respective mobile station according to the target value Q of communication quality.
In addition, in the foregoing quality determining means, the target values q and Q of communication quality can be handled through a process of converting to thermal noise power, a reciprocal of a bit error rate (BER) per unit time, a ratio of signal power after back-diffusion to thermal noise power or a ratio of signal power per bit to noise power density.
In the foregoing communication system of the present invention, the wireless communications that take place between the base station and a plurality of mobile stations can be performed by spread spectrum communications. At this time, in the communication quality determining means, the target values q and Q may also be handled through a process of converting to thermal noise power derived by calculation from a ratio of signal power after back-diffusion to thermal noise power or a ratio of signal power per bit to noise power density and a diffusion rate of spread spectrum communications. Further, the spread spectrum communications may also be replaced with CDMA communications.
According to the foregoing communication methods and communication systems of the present invention, such communication conditions in wireless communications as transmitting power of the base station and mobile stations, signal transferring speed, communication quality of received signals and the like can be designated arbitrarily at the mobile station side and, therefore, the communication status can be set up optimally so as to match the nature of information transferred by the user and the communication environment involved with the user.
In addition, by detecting and watching the status of congestion in communication, the on-going condition of communication can be correctly grasped, thereby allowing the base station""s ability to be utilized correctly and also to the maximum. Also, by grasping the status of congestion in communication under the same communication conditions as applicable in controlling the communications with mobile stations such as transmitting power, transferring speed, communication quality and the like, the base station""s communication ability can be readily utilized correctly and also to the maximum.
Since communication quality can be converted to thermal noise power, a reciprocal of a bit error rate (BER), a ratio of signal power after back-diffusion to thermal noise power or a ratio of signal power per bit to noise power density, the level of communication quality can be optimally selected, as needs require, according to the environment involved with communication systems and communication facilities.
Also, communication fees are charged according to the communication conditions designated at the mobile station side and, therefore, the use can set up the communication conditions and communication costs optimally.
By employing spread spectrum communications and CDMA communications in wireless communications for the communication method and communication system of the present invention, the benefits as described in the above are made to function more effectively.